Protective device



Aug.12,'1947. C.W .KUHN ETAL 2,425,623

PROTECTIVE DEVICE- Filed Feb. 4, 194 2 Sheets-Sheet i INSULQTfJ/T lb [4G 2 Patented Aug. 12, 1947 Rosing, Whitefish Bay, Wis assignors toCutler-Hammer, Inc.,- Milwaukee, Wis a corporation of Del awareApplication February- 4, 1943, Serial No? 4 745682 This inventionrelates toprotective devices for electric circuits and is particularlyapplicable to protective devices of the type disclosed in the Kuhn etal. Patent No. 2,310,531, of February 9; I943;

The aforementioned patent discloses an ambient temperature compensated:overload relay, andvthe present invention has among its objects toprovide a relay of this type which is highly shocks-proof, or in otherwords capable ofperforming: properly and withstanding damage whensubjected to shockss'u'ch as are encountered on board naval. vesselsupon: bombing and: torpedo ing thereof.

Another object is to provide an overload relay ofthe: aforesaid t ypewitl'l mechanism: which acts upon inertial movement of the:relayoperating mechanism under the action of: severe shock to preventopening of. the relay contacts.

Another object is to provide a shock-moor mechanism for relays of theaforesaidwhich is simple,. ruggedi and: inexpensive 'in construction andpositive'and reliable inoperation.

Various other objects and:- advantages oi the invention: willhereinafter appear-t The accompanying; drawings illustrate an embodimentof the: invention which willnow be described, iti'bein'gr understoodthat: various modifications may be made: i'n thefi embodiment;illustrated without departing from the spiritand scope of the appendedclaims';

In the drawings,

Figure 1 is a side elevational view ofa relay embodying: the invention,the relay: b'eirlg-v shown in: set positions and a part of theenclosing. casing therefor being removed}:

Fig. 2 is aview similar-to that show-n in Fi'g. 1withupartssbroken'raway'andishown in sectibnl and illustrating inertial"operation oi: the relay: under the: action ofzshock; and,

Figs'r3 and 4" are secti'o'nalrviews: on lines 3 -3 and 4'-4,respectively, of Fig. 1;

Referring to the accompanying; drawings, the sameillustrate arr.overload: responsive relay of the type disclosed. in the; aforementionedpatent, the operating mechanismof said relay being housed between twocomplementary casing sections l and l which are formed of molded in'-sulating-jmaterial and:are mounted upon the front face of a I verticallydisposed insulating]: base Z;

Briefly described the relay" is providediwith a ofnormallyengaged.spring contact fingers 3 and l which are mountedupon-=the front face ofinsulating 'base, 12 and-are separable: by an insulatlng finger 5'."Finger- 5=- mounted upon a bar 8 fi'xed to a reciprocablepush buttonelement 1: and saidpush button element is slid'ably sup ported betweenthe casing: sections i and l and is biased tomove forwardly by a spring8. Pushbutton element 1' is normally held" in the de'-' pressed positionshown by full lines in Fig. 1 to maintain finger 5' out of engagementwith con-- tact fingers 3 and: 4* by a thermal overload responsivemechanism including a latch 9 anda cooperating verticallydisposed lever H3.

Latch 9 is pivotally mounted u-poh push button element 1- and isnormally held againstthe action of a biasing spring H inengagement withthe lower end 0t lever W by a solder type thermal responsive element--r2. Element I2 is: mounted upon push button element 1 and is responsiveunderthe action of a heater coil l-3= to triplatch 9 outofengagementwith lever It upon a-prede= terminedoverload current condition insaidcoil; Upon tripping 0t latch 9 push button element I moves forwardlyunder the action ofspring 8 into the. dotted line; position shown inFig. 1- to effect; separation oicontact fingers 3 and 4 by movement ofinsulating finger 5- therebetween. Depressionof push button-element Ieffects resetting; ofthe relay in the positionshown' in Fig 1.

Lever H) has it'supper end pivoted-upon a'pi-n 3| carriedbetweenthe-casing sections I andl and saidil'ever isoperable by atemperatureresponsive' diaphragm: device [4 against theaction of an adiust'ableloading spring I5 to automati callyad justthermal responsive element: I2 with respect to heater. coil 13' so that overload operation of therelayv is substantially uninfliienc'ed by ambient temperature changes...

When the above described relay is in set position severe shockmayprouucc accelerating forces Whicl'i' eiiect forward" movementOfpilsfi button element 1' and the parts connected thereto against thebiasing" action ofloading spring'. [5; In accordance with the presentinventionthe mechanism which will now be" described isprovided forpositively blocking insulatingr finger 5 out of engagement with contactfingers 3 and 4 uponrorwar'd movement of push button element 1 under theaction of'shocli.

Insulatingfinger 5 -is piyotallymountedupon-a pin it carried byanupstanding part1 fixed to the rear end of bar Wanda is yieldingly heldagainst counterclockwise -rotation -outof: the'vertical positiom shownin Figc'lby: a spring I8.

Upon tripping of: the relayunder ovcrload condh tionsspringl8-maintainsinsulating-finger i in s in the vertical position shown in Fig. 1 duringmovement thereof between contact fingers 3 and 4.

A bell crank lever 19 having arms 20 and 2| is provided for blockinginsulating finger 5 against movement into engagement with contactfingers 3 and 4 upon forward movement of push button element 1 out ofthe position shown in Fig. 1 under the action of shock. Bell crank leverI 9 is fixed to the lower end of a vertically disposed pivot pin 22 andsaid pivot pin is rotatably supported within a bearing bushing 23 heldwithin an opening formed in the opposing faces of walls 24 and 24 on theinterior of casing sections l and l Arm 20 extends rearwardly from pivotpin 22 and is bent upwardly for engagement with insulating finger 5 at apoint above the pivot pin it. Arm 2i has a forwardly extending link 25pivotally connected to the free end thereof and as shown in Fig. 4 saidlink is located to one side of lever i and is slidably supported withina groove 26 in casing section l Link 25 has an inwardly bent portion 21on the front end thereof to be engaged by lever l0 upon forward movementof said lever beyond the range through which it moves for ambienttemperature compensation. Bell crank lever I9 is biased to rotate in acounterclockwise direction (Fig. 4) by a coil spring 28 and said leveris normally held in the position shown in Fig. 4 against the action ofsaid spring by engagement of arm 2| with a stop surface 29 on casingsection l With bell crank lever I9 in th position shown in Fig. 4 thearm 20 thereof is out of the path of insulating finger and the relay isthus adapted to operate as hereinbefore described under overloadconditions. However, upon forward movement of the push button element 1under the action of shock, lever l0 engages projection 21 on link 25 tomove bell crank lever I 9 in a clockwise direction out of the full lineposition shown in Fig. 4 so that arm 20 assumes a position in the pathof insulating finger 5. This operation occurs prior to movement ofinsulating fingei- 5 into engagement with contact fingers 3 and 4. Uponcontinued forward movement of push button element I under the action ofshock insulating finger 5 engages arm 20 of bell crank lever l9 and isrotated against the action of spring i8 as shown in Fig. 2 to preventengagement thereof with contact fingers 3 and 4. As is apparent,rotation of insulating finger 5 against the action of spring [8 permitsfull movement of push button element 1 against the action of loadingspring [5 into the dotted line position shown in Fig. 1 for dissipationof the accelerating forces produced by shock.

As shown in Fig. 3, stationary contacts 3 and 4 are located betweenprojections 30 and 30* on the interior of casing sections l and l Saidproj ctions prevent separation of contacts 3 and 4 under the action ofshock by limiting vibrational movement thereof.

What we claim as new and desire to secure by Letters Patent is:

1. The combination with a switch having operating means biased formovement to effect a given condition of said switch, means engaging apart of said operating means when moved to effect a. different givencondition of said switch and subjecting said part to a preponderatingbias against which it has play under shock, and movable means operatingas a function of such play of said part positively to block change inthe condition of said switch for a temporary period terminated bysubsequent stabilization of said part under said preponderating bias.

2. A condition responsive switch having an associated control mechanismincluding a member normally movable within a given range and movablebeyond said range under an abnormal condition, and means associated withsaid member for preventing a change in the condition of said switch uponmovement of said member beyond said range.

3. In a protective device, in combination, a movable switch element, anoperating member therefor biased to move into a given extreme position,a yieldable operating connection between said element and said operatingmember for moving said switch element into a given circuit controllingposition upon biased movement of said operating member into said givenextreme position, an overload responsive mechanism for normally holdingsaid operating member out of said given extreme position and forsubjecting the same to a Dreponderating bias against which it has a playunder shock, and means operating as a function of said play of saidoperating part for positivel blocking said switch element againstmovement into said circuit controlling position for a temporary periodterminated by subsequent stabilization of said part under saidpreponderating bias.

4. In a protective device, in combination, a movable switch element, anoperating member therefor biased to move into a given extreme position,a yieldable operating connection between said switch element and saidoperating member for moving said switch element into a given circuitcontrolling position upon biased movement of said operating member intosaid given extreme position, an overload responsive mechanism fornormally holding said operating member out of said given extremeposition and for subjecting the same to a preponderating bias againstwhich it has a play under shock, and means operating as a function ofsuch play of said operating member for positively blocking said switchelement against movement into said circuit controlling position, saidyieldable operating connection acting upon blocking of said switchelement to permit full movement of said operating member into said givenextreme position under the action of shock.

5. In a protective device, in combination, a movable switch element, anoperating member therefor biased to move into a given extreme position,a yieldable operating connection between said switch element and saidoperating member for moving said switch element into a given circuitcontrolling position upon biased movement of said operating member intosaid given extreme position, an overload responsive mechanism fornormally holding said operating member out of said given extremeposition and for subjecting the same to a preponderating bias againstwhich it has a play under shock, means operating as a function of suchplay of said operating member for positively blocking said switchelement against movement into said circuit controlling position, saidyieldable operating connection acting upon blocking of said switchelement to permit; full movement of said operating member into saidgiven extreme position under the action of shock, and a temperatureresponsive device for adjusting said overload responsive mechanism tomaintain the action thereof substantially uniform under varying ambienttemperature conditions.

6. In a protective device, in combination, a

movable switch element, an operating member therefor biased to move intoa given extreme position to move said switch element into circuitinterrupting position, a current responsive overload latching mechanismassociated With said member, a condition responsive device having aspring biased part normally engaged by said latching mechanism to holdsaid operating member out of said given extreme position, said springbiased part being adjustable through a given range by said device tovary the current value at which said latching mechanism responds, andbeing movable against its bias beyond said range under the action ofshock, and means associated with said spring biased member and actingupon movement thereof beyond said range to positively block said switchelement against movement into circuit interrupting position.

7. In a protective device, in combination, a movable switch element, anoperating member therefor biased to move into a given extreme positionto move said switch element into circuit interrupting position, acurrent responsive overload latching mechanism associated with saidmember, a condition responsive device having a spring biased partnormally engaged by said latching mechanism to hold said operatingmember out of said given extreme position, said spring biased part beingadjustable through a given range by said device to vary the currentvalue at which said latching mechanism responds, and being movableagainst its bias beyond said range under the action of shock, meansassociated with said spring biased member and acting upon movementthereof beyond said range to positively block said switch elementagainst movement into circuit interrupting position, and a yieldingoperating connection between said operating member and said switchelement permitting full movement of said operating member into saidgiven extreme position under the action of shock upon blocking of saidswitch element.

CLARENCE W. KUHN.

THEODORE F. ROSING.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

